Article Text
Abstract
Background Nearly 0.7 billion workers are involved in the shift work system, leading to concerns about its potential impacts on the large-scale population mental health. This study aimed to synthesise evidence of the associations between matched chronotype and the risk of poor mental health among shift workers.
Methods Six computerised databases were searched from inception to September 2022. Observational studies were selected if they reported any association between common mental health parameters and chronotype scores/types of shift workers. The Preferred Reporting Items for Systematic Reviews and Meta-analyses checklist was followed. We extracted adjusted risk estimates to calculate pooled effect sizes and explore sources of heterogeneity. The study was registered in PROSPERO: CRD42022357437.
Results Fourteen studies including 49 909 workers were identified. Ever shift workers had a higher risk of poor mental health than the day workers (pooled OR 1.15, 95% CI 1.03 to 1.28; I2=14%, p=0.29), with the evening chronotype ever shift workers having a 1.47 times higher risk than those who worked during the day (pooled OR 1.47, 95% CI 1.13 to 1.91; I2=42%, p=0.16). Sensitivity analysis excluding studies with the highest risk of bias of each group demonstrated consistent findings.
Conclusions Evening chronotype ever shift workers have poorer mental health than shift workers with other chronotypes. Chronotype remains unrecognised in the contemporary rostering system, making it a hidden contributor to occupational mental health. Work-related physical and mental stresses may be prevented/mitigated with further investigation on optimising shift work schedule combined with individual chronotype preference.
- mental health
- meta-analysis
- occupational health
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Data availability statement
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Footnotes
BL and GL contributed equally.
Contributors LAT is the guarantor of the manuscript and is the principal investigator of the project, designed and supervised the entire study. BL designed the study, reviewed the literature, extracted and analysed the data, and drafted the manuscript. GL reviewed the literature, extracted the data, and reviewed the manuscript. YKW, JWYC and AH critically reviewed and revised the manuscript. PMYL and JYTM gave comments and reviewed the manuscript.
Funding The Health and Medical Research Fund (Ref. No. 18190471), the Research Grants Council-General Research Fund (RGC Ref. No. 14604020) of the Hong Kong Special Administrative Region, and lnt'l TripartiteCollaboration to Advance Exposome Research-lnnovative Public Health Exposome Global Projects and BioData Approach of the Chinese University of Hong Kong (Ref. No. EC/2017/006), Hong Kong Special Administrative Region, China.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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